1. Field of the Invention
The present invention relates to a radiation detecting apparatus for detecting radiation that has passed through a subject and converting the detected radiation into radiation image information, and a radiation image capturing system incorporating such a radiation detecting apparatus therein.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing systems, which apply radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which in turn captures a radiation image from such radiation. Known forms of radiation conversion panels include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing radiation energy representing a radiation image in a phosphor, and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor.
The radiation film, with the radiation image recorded therein, is supplied to a developing device to develop the radiation image. Alternatively, the stimulable phosphor panel is supplied to a reading device in order to read the radiation image as a visible image.
In an operating room or the like, it is necessary to read recorded radiation image information immediately from a radiation conversion panel after the radiation image information has been captured therein for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a direct-conversion-type radiation detector including solid-state detectors for directly converting radiation into electric signals, or an indirect-conversion-type radiation detector comprising a scintillator for temporarily converting radiation into visible light, and solid-state detectors for converting the visible light into electric signals to read detected radiation image information.
Heretofore, there has been proposed a radiation detecting apparatus housing therein a radiation detector (radiation conversion panel), which is flexible enough to match itself to desired surface shapes of the patient, as disclosed in Japanese Laid-Open Patent Publication No. 2003-070776.
However, the flexible radiation detector or radiation conversion panel of the proposed radiation detecting apparatus cannot easily be placed in storage during periods when it is not used to detect radiation having passed through a subject, i.e., when it is not used to capture a radiation image of a subject. On the other hand, when the flexible radiation conversion panel is used to detect radiation having passed through a subject, i.e., when it is used to capture a radiation image of the subject, the irradiated surface (image-capturing surface) of the radiation conversion panel cannot be kept flat with respect to the subject.
Japanese Laid-Open Patent Publication No. 2003-070776 discloses a flexible radiation detector or radiation conversion panel, which includes a scintillator for converting radiation that has passed through a subject into visible light, and solid-state detectors for converting the visible light into electric signals representative of radiation image information. Such a flexible radiation detector or radiation conversion panel is housed in a flexible case.
When external light is applied to the radiation conversion panel, the solid-state detectors convert the visible light converted from the radiation by the scintillator and also external light into electric signals. Therefore, a signal component of the electric signals, which corresponds to the external light, results in noise with respect to the radiation image information. Although it is desirable that the radiation conversion panel be shielded against external light to eliminate such noise, there is nothing disclosed in Japanese Laid-Open Patent Publication No. 2003-070776 for shielding the radiation conversion panel against external light.
Japanese Laid-Open Patent Publication No. 2003-172783 discloses a cassette-type radiation detecting apparatus incorporating solid-state detectors. The disclosed cassette-type radiation detecting apparatus is rigid as a whole, and therefore cannot be matched to the surface shape of a patient to be imaged. Further, the cassette-type radiation detecting apparatus is so heavy that it cannot be handled with ease.
As described above, Japanese Laid-Open Patent Publication No. 2003-070776 discloses a flexible radiation detecting apparatus, which can match itself to the surface shape of a patient to be imaged thereby. However, since the disclosed radiation detecting apparatus includes drive circuits, which are disposed in a direction in which the radiation detecting apparatus itself is flexible, the radiation detecting apparatus is not sufficiently flexible. Furthermore, the disclosed radiation detecting apparatus includes readout amplifiers, which tend to limit the flexibility thereof.